3.5 v8 dies after 10 mins

Muddy goose · May 1, 2019

discool said:
What makes U think it’s fuel, early posts just suggest it’s a maybe, could be or seems.
So are u sure your issue is fuel related, u state u wait 5 minutes and “ then up and going again” so what is the significance of that delay, what’s happening during that period? I’m wondering as so far you done done everything, there’s nothing left, or is there.

Do you have electronic ignition fitted as that can play up and cut the engine, but after a short wait the engine will start like nothing has happened.

I wonder if even the new set up is being affected by the heat I could try fitting a remote amp they supply as my V8 is 10.5cr so runs hotter than the low cr although the cooling system runs norm the oil seems to run warm. What throws me is it still had the issue with the old dizzy setup

Shippers · May 1, 2019

The only other thing I can think is that as engine heats up you're getting an air leak at the inlet manifold gasket due to expansion it's a long shot I know but youv'e systematically done everything else...

Muddy goose · May 1, 2019

Shippers said:
Can you put a piece of clear pipe in return to tank that's what I did and it shows air in it when it has stood for a while...weeks not days...this would show fuel starvation...

Hi
Do you mean a clear pipe to show the return fuel from the carbs?

marjon · May 1, 2019

Ok need to start throwing another idea in. Along the lines of @Shippers
How hot does it get under your bonnet?
Does it quit if it’s sat with the bonnet up and you get it warmed up? Or just if you try and drive it with some loading(loud pedal)?

J

Shippers · May 1, 2019

Yes...when you start engine if through fuel starvation the carbs are empty air will bubble down clear pipe but to be honest I don't think that's your problem but will rule out fuel problem...

Muddy goose · May 1, 2019

Shippers said:
The only other thing I can think is that as engine heats up you're getting an air leak at the inlet manifold gasket due to expansion it's a long shot I know but youv'e systematically done everything else...

I had the manifold off to change over a noisy follower (crappy cheap
Rimmerbro’s) of course all went back down at correct torque settings I can of course recheck

Shippers · May 1, 2019

Muddy goose said:
I had the manifold off to change over a noisy follower (crappy cheap
Rimmerbro’s) of course all went back down at correct torque settings I can of course recheck

Did you use a smear of sealant on gasket and which gasket the one with the foam backing?....

Muddy goose · May 1, 2019

marjon said:
Ok need to start throwing another idea in. Along the lines of @Shippers
How hot does it get under your bonnet?
Does it quit if it’s sat with the bonnet up and you get it warmed up? Or just if you try and drive it with some loading(loud pedal)?

J

Hi Yes it gets very warm underneath. It’s ok just running with bonnet up or down it’s when you push on the loud pedal it shows up straight away if you kept it at 1500-2000 rpm with very light pedal it will go for longer

Muddy goose · May 1, 2019

Muddy goose said:
Hi Yes it gets very warm underneath. It’s ok just running with bonnet up or down it’s when you push on the loud pedal it shows up straight away if you kept it at 1500-2000 rpm with very light pedal it will go for longer

Driving along that is not parked up you can rev as much as you like then.

Muddy goose · May 1, 2019

Shippers said:
Did you use a smear of sealant on gasket and which gasket the one with the foam backing?....

Hi No sealant as it is a composite one and it had only been down for 200 miles and I had the block skimmed when I rebuilt the engine

Muddy goose · May 1, 2019

I will be wrapping the exhaust manifolds to keep on top of the heat for the warmer summer months

Muddy goose · May 1, 2019

Muddy goose said:
Hi Yes it gets very warm underneath. It’s ok just running with bonnet up or down it’s when you push on the loud pedal it shows up straight away if you kept it at 1500-2000 rpm with very light pedal it will go for longer

Shall I take a temp reading?

Muddy goose · May 1, 2019

I must add originally last summer when I was running her in, of course very light on pedal and no more then 2000rpm at around 250miles thats when on 10-25mile journey it would cut out sit around for ten mins and back on with the journey, hence the thought of under bonnet heat and fuel vaporizing to begin with. The journeys have just got shorter and shorter now within a 5 min drive When running warm or cold.

Shippers · May 1, 2019

After it cuts out do you switch off ignition let it sit then how long before it will re-start? and does it crank for a while before it fires?...

Ratae · May 1, 2019

When it dies have you checked for a spark?
Carry a spare plug & use it with any of the leads against the block.

Muddy goose · May 1, 2019

Ratae said:
When it dies have you checked for a spark?
Carry a spare plug & use it with any of the leads against the block.

I’ve got an in-line spark plug light I will pop it on and check

Muddy goose · May 1, 2019

Shippers said:
After it cuts out do you switch off ignition let it sit then how long before it will re-start? and does it crank for a while before it fires?...

I’ve tried both ways it will always start but the longer I wait the further it will go

Shippers · May 1, 2019

Muddy goose said:
I’ve tried both ways it will always start but the longer I wait the further it will go

Yes but does it crank without firing or starts first turn...I would expect if fuel starvation it would crank for a while before firing...I also had a problem with mine there was a leaf in the tank which got sucked up to the supply pipe cutting of supply then it would sink down on switch off only to be sucked up again baffled me for ages till I stripped it all down...lol

wireman · May 1, 2019

Check your rotor arm, does the brass strip on top move at all? If so replace it. Check your dizzy cap for cracks as well, just because they are new doesn't mean they are serviceable.

Muddy goose · May 1, 2019

Shippers said:
Yes but does it crank without firing or starts first turn...I would expect if fuel starvation it would crank for a while before firing...I also had a problem with mine there was a leaf in the tank which got sucked up to the supply pipe cutting of supply then it would sink down on switch off only to be sucked up again baffled me for ages till I stripped it all down...lol

I will try in the morning

3.5 v8 dies after 10 mins

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